Spiegel, Murray R <br/><br/>
Theory and problems of calculus of finite differences and differential equations 

 - New York  Mc Graw - Hill  1971 
 - 259p. 
<br/><br/><label>Subjects--Index Terms: </label>Finite differences  Differential equations 
<br/><br/><label>Universal Decimal Class. No.: </label>517.9   / SPI